Machine for generating power transmitting surfaces and method



July 9, 1940.

R. P. RENTZELL 7 2,207,177 MACHINE FOR GENERATING POWER TRANSMITTINGSURFACES AND METHOD Filed Dec. 1, 193a 12 Sheets-Sheet 1 A July 9, 1940.

R. P. RENTZ ELL MACHINE FOR GENERATING POWER TRANSMITTING SURFACES ANDMETHOD 12 Sheets-Sheet 2 Filed Dec. 1, 1.938

July 9, 1940. R. P. RENTZELL 2,207,177- MACHINE FOR GENERATING POWERTRANSMITTING SURFACES AND- METHOD Filed Dec. 1, 1938 12 Sheets-Sheet 3YQ, 1940. R. PNRENTZELL 2,207,177 MACHINE FOR GENERATING POIERTRANSMITTING SURFACES AND METHOD 12 Sheets-Sheet 4 Filed Dec. 1, 1938 y9, R. P. RENTZELL 2,207,177

MACHINE FOR GENERATiNG .-PO.WER TRANSMITTING SURFACES AND METHOD FiledDec. 1, 1938 12 Sheets-Sheet 5 y 9, 1940- R. P. RENTZELL 2,201,177

MACHINE FOR GENERATING POWER TRANSMITTING SURFACES AND METHOD Filed Dec.1, 1938 12 Sheets-Sheet '6 July 9, 1940. R. P. RENTZELL MACHINE FORGENERATING- BQWER TRANSMITTING SURFACES? AND METHOD Filed Dec. 1, 1938l2; Sheets-Sheet T July 9, 1940.

R. P. RENTZELL.

MACHINE FOR GENERATING POWER- TRANSMITTING SURFACES AND METHOD 12Sheets-Sheet 8 Filed; Dec. 1, 1938 9,1940. 7 R. P. RENTZELL 2,207,177

MACHINE FOR GENERATING POWER TRANSMITTING SURFACES AND METHOD Filed Dec.1, 1938 12 S heetsSheet 9 y 9, R. P. RENTZELL' 2,207,177

MACHINE FOR GENERATING POWER TRANSMITTING SURFACES AND METHOD Filed Dec.1, 1938 12 Sheets-Sheet l0 July 9, 1940. i R P, RENTZELL 2,207,177

MACHINE FOR GENERATING POWER TRANSMITTING SURFACES AND METHOD Filed Dec.1, 1938 12 Sheets-Sheet 11 July 9, 1940. R. P. RENTZELL MACHINE FORGENERATING POWER TRANSMITTING SURFACES AND METHOD Filed Dec. 1, 1938 12Sheets-Sheet 12 WZEZEU to Z0.

luff-Won Patented July 9, 1940 MACHINE FOR GENERATING POWER TRANS-BETTING SURFACES AND METHOD Robert P. Rcntzell, Lutherville, Md,assignor to The Black & Decker Manufacturing Company, v a corporation ofMaryland Application December 1, 1938, Serial No. 243,375

26 Claims.

The invention relates to the formation or generation of the toothsurfaces, or the power transmitting surfaces of power driven hand toolclutches of the type in which the clutch members engage and release byrelative motion in the direction of the clutch axis, the object being togenerate these surfaces in such form as to maintain contact of the toothsurfaces of the respective clutch members throughout the overlappingarea of the tooth surfaces, or at least throughout the radial length ofthe teeth up to the instant of release. To this end the tooth surfacesof one or both clutch members are of helical or substantially helicalarrangement either about the axis of the clutch or about an axis closeto and substantially parallel to the clutch axis. Where the toothsurfaces of both clutch members are radial about the axis of the clutch,the tooth surfaces, or power transmitting surfaces, are in contactthroughout their overlapping area up to the point of release. Where oneclutch member has its power transmitting surfaces helical about an axisclose to and parallel to the clutch axis, and the other member has atooth of the transverse pin or similar type, the clutch teeth ifdesigned to cooperate in the manner hereinafter described, will have afull line contact throughout the radial length of the teeth up to thepoint of release. Both types of clutch 3o are'fully disclosed in aco-pending application of Glenn H. Wilhide, Number 156,700, filed JulyWhile it is possible to produce such clutch teeth by means of a specialcutter, this requires a different cutter for each size of tooth, and thedifliculty encountered from distortion in the heat treatment which isnecessary to production of the tooth surfaces by cutting, and the manycutters which would be necessary to generate m all of the clutch teethof the various sizes, and the time required to generate teeth in thisway are all factors which together made the cutting method relativelyinefficient, and therefore undesirable. The present invention relates toa machine for generating or forming the helical surfaces of the clutchteeth by grinding, the

grinding method also being a feature of the invention, and the machineshown being usable for grinding other helical and other tooth surfaces.

It is of interest that this machine was developed in connection with theproduction of portable power-driven tools of the overload release type,particularly nut runners, bolt driving machines, and screw drivers. Allof these machines are equipped with a jaw clutch which drives onerotating jaw from the other, both being on the same axis, and the clutchis released by the motion of one or both :members in the direction ofthe axis, separating the clutch members, and 9 particularly, theteeth.01 power transmitting surfaces thereof. i

In accordance with the grinding method of the invention, the clutchblank is placed on a spindle or arbor, the clutch teeth being formed(It) in a preliminary way, either by grinding, or by machining. Thespindle on which the blank is mounted is concentric with the clutchaxis, and is, in turn, mounted upon presenting mechanism secured to ashaft which is at right angles to the spindle, the blank being sopresented that the central radial line ofthe power transmitting surfaceof the clutch blank being treated, is on the center line or axis of thelatter shaft. Means is also provided for rocking the said shaft througha uniform angle about its axis and at the same time moving it in thedirection of its axis, and this motion serves to pass the powertransmitting surface of the clutch or clutch tooth over a rotatinggrinding wheel which has its cutting surface arranged with the contactline or element thereof which engages-and forms the tooth or powertransmitting surface in radial relation to the sliding or substantialshaft. The word over as used in this connection in the specification andclaims has reference to the passing of the tooth and wheel, onerelatively to the other in grinding relation, rather than to therelation of the wheel and tooth, in that one is above or below theother, which latter relation is immaterial. In this way the powertransmitting surface which is being formed on the clutch member is drawnin contact with and over the rotating grinding wheel, which is rotatedabout an axis at right angles to the clutch axis thus generating a powertransmitting surface which is helical about the axis of the clutch, orif desired, about an axis parallel to or substantially parallel to theclutch axis and spaced away from the said clutch axis depending upondesign of the cooperating clutch members and their arrangement in thefinal assembly of the clutch.

A machine embodying the features of the invention in the preferred formin so far as it relates to the apparatus, said machine being adapted togenerate or grind the power transmitting surfaces of the clutch membersabove identified, and to be thus used in the performance of the methodof the invention isdescribed in the following specification, andillustrated in the drawmgs.

In the drawings:

Figure 1 is a front elevation of the machine looking from the positionof the operator, and showing the blank arranged for generating orgrinding the power transmitting surfaces which engage in right handedrotation of the clutch.

Figure 2 is an elevation looking from the left in Figure 1 at thegrinding wheel and clutch unit presenting mechanism.

Figure 3 is a clamp for holding the table in the clutch tooth generatingposition of the machine.

Figure 4 is a top plan view of the clutch unit holding and presentingmechanism at the outer end of the swinging arm beneath the grindingwheel.

Figure 5 is fragmentary front elevation of the inner end of the swingingarm and the operating mechanism for the same.

Figure 6 is a section on the line 6-6 in Figure 5, looking toward theright in said figure.

Figure '7 is a fragmentary plan view of the operating lever forpresenting the clutch unit justable path, or guide plate, the front ofthe machine being at the right in this figure.

Figure 9 is a top plan view of the construction shown in Figures 5, 6,and 8, the casing being broken away to show the inner construction and"the bearing tube likewise being broken away to show the underlyingportion of the mechanism.

Figure 10 is an elevation looking from the front at the blank presentingmechanism beneath the grinding wheel showing a blank thereon.

Figure 11 is an elevation of the grinding wheel trueing diamond andsupport together with a fragment of the machine table.

Figure 12 is an elevation continuous with Figure 5 showing the portionof the casing and parts enclosed therein immediately at the right ofFigure 5, the operating lever for moving the blank as hereinafterdescribed being broken away.

Figure 13 is a section on the line |3I3 in Figure 5 showing the slidingrotation bearing for the shaft for supporting and operating the swingingFigure 1'7 is a fragmentary view showing the gauge with a spacing platein operative relation thereto and the diamond in operative position fortrueing the wheel for generating teeth for cooperation with a pin in thepin type of clutch.

Figure 18 shows two clutch members of the helical surface type generatedby this machine,

the clutch members being in operative relation,

and the helix being of the radial type, the two clutch members beingsimilar, and the view being enlarged.

Figure 19 shows a clutch, one member of which lis a transverse pin, theother member being a helical tooth surface generated about an axis 'ingshown which is offset about half of the thickness of the pin from theaxis of the clutch.

Figure 20 is a view looking at the clutch of Figure 19 from the right insaid figure.

Figure 21 is a front elevation, i. e. looking from the same point ofview as Figure 1 showing a clutch blank of the radial helix type, theblank being in a position in which its axis is in the same verticalplane as the axis of the grinding wheel which is the position forsetting the machine prior to cutting, the arrangement shown is forgenerating or grinding the back surface used only in left handedrotation of the clutch.

Figure 22 is a left side elevation of this same subject matter andarrangement, the clutch blank also being shown in broken lines in theposition to which it is tipped at the end of the cut in cutting theangle tooth particularly described in this specification.

Figures 23, 24, and 25 show fragmentarily and enlarged, the relativepositions of the grinding wheel and blank as the blank is rocked tendegrees, fifteen degrees, and twenty degrees respectively from theinitial position corresponding to Figure l in the cutting operation ashereinafter described, the generating or grinding operation beingapplied to the surface which engages in right handed rotation and theblank being moved radially as it is rocked.

Figure 26 is a view closely similar to Figure 25 but showing theposition of the grinding wheel in relation to the blank after the workholder has been swung to compensate for the movement of the blank awayfrom the wheel as shown in Figure 25.

Figure 27 is a view showing the relation of blank and wheel for grindingthe surface of the tooth which engages in right hand rotation of theclutch, the broken lines indicating the position of the grinding wheelprior to dropping it for grinding the offset tooth for use with the pintype of clutch member, the full line position of the wheel being that inwhich the axis of the clutch is in the vertical plane of the wheel axis,this being the position for setting the machine and corresponding exceptas stated, to the full line position, Figures 21 and 22.

Figure 28 shows the blank moved away from the wheel from the position,Figure 2'7, to compensate for the rotation of the blank which, with thewheel lowered as described so that its cutting plane is below the axisof the wheel, tends to cause the grinding wheel to cut into the base ofthe tooth.

Figure 29 shows the wheel and clutch member of the type shown in Figures2'7 and 28, the clutch blank being in relation to the wheel which thesemembers occupy at the end of the cutting stroke, the blank being rotatedthrough an arc of I Figure 30 is a fragmentary sectional view ofone-half a blank of the offset type, the blank having been rotated fromits initial position in Figure 2'7 as to the position, Figure 29, andthe axis and the center line of the tooth surface bein both positions.This may be treated as a section on line 30-30 in Fig. 31.

Figure 31 is a fragmentary plan of a clutch member of the radial helicalsurface type looking in the direction of the axis showing the dimensionsof the standard clutch unit produced in this way.

Figure 32 is a fragmentary front view corresponding to Figure 1 on anenlarged scale of the grinding wheel and the tooth about to be out inthe initial position of setting the machine in which the axis of theclutch blank is in the vertical plane of the axis of the wheel.

Figure 33 is a View looking at the subject matter of Figure 32 from theright.

Figure 34 is a view similar to Figure 32, the blank having een moved tothe left to bring the inner edge of the tooth into cutting plane andturned about a transverse axis through an angle of 10 which is theinitial position of the blank in the actual grinding operation.

Figure 35 is a similar View showing the blank moved to a position inwhich the cutting plane of the grinding wheel is in the center of thetooth surface measured radially, the blank having been rotated throughan angle of 15, the angle of the tooth of'the center in the exampleshown being 15 divergent from the clutch axis.

Figure 36 is a similar View showing the end of the grinding operation,the blank having been rotated through an angle of 20, and the outer edgeof the tooth in a radial direction being in the cutting plane of thegrinding wheel, so that its outer edge as ground is 20 to the axis.

The operation considered in a general way, having particular referenceto Figure 1, consists in moving the blank transversely through thecutting plane of the grinding wheel, and in cutting relation to the sameas the wheel rotates, the blank moving in the direction of its radiusand at the same time being rocked or tipped about said radius whichconstitutes an axis transverse to the axis about which the clutch memberrotates in its operation when installed in a power driven tool orsimilar apparatus for which the clutch members generated in this way areprovided. In one operation illustrated, the axis about which the blankis rocked during the grinding or generation of each tooth surface isradially disposed as to the blank, and locatedin, or substantially in,the generated or ground surface, and about half way between the base andthepeak of the tooth. The generated surface if extended to the center ofthe clutch, would in the radial type, coincide or tend tocoincide withthe clutch axis and in non radial type which is shown as cooperatingwith a pin clutch member, said surface if extended inwardly, would tendto coincide with a line substantially parallel to the clutch axis andspaced therefrom in correspondence with the offset of the pin surfaceswhich engage the generated tooth surfaces. It is therefore foundexpedient in generating radial helical surfaces to use an initialposition, one in which the grinding element or line of the wheelcoincides with the clutch axis which, in this machine, brings the axisof the blank into the vertical plane of the wheel axis. From thisposition the blank is moved in the direction of, and rocked about orsubstantially about its radius located intermediately of the generatedtooth surface.

In cutting the clutch member which cooperates with a pin forming the pintype of clutch, the grinding wheel is moved downwardly by a distancewhich equals or closely corresponds to half the thickness of the pinmeasured in the direction of the radius which causes some variationidentified through an arc of 20, the inner end of the tooth surfacetowards the axis being at an angle to the axis of 10, the center of thetooth being at an angle of 15, and the outer edge of the tooth "being atan angle to the. axis (if-20. This angle can be varied, as desired. Theangles and dimensions given apply to a clutch blank which is two inchesin outside diameter, and has a central hole for the shaft or the like,one inch in diameter which makes the toothof the radial length ofone-half inch. This is merely a standard size of clutch made .by theassignee on'the machine illustrated. It is for example only and has nodirect bearing on the patentable features of the invention.

Referring to the drawings by numerals each of which is used to indicatethe same or similar parts in the different figures, and havingparticular reference to Figure 1;

The machine as shown comprises a' standard i with a base 2' which issecured tothe floor.

Mounted on this standard is a table 2 which in the grinding operation isstationary being secured by a clamp 3 which need not be described indetail except that itserves in combination with as shown in Figure 1,means not shown controlled by hand wheel 4 for moving the table in theplane of Figure 1; these motionsof the table are not possible or desiredwhen the table is clamped by I the clamping member figure number 3, forthe grinding operation.

The table is provided with a pedestal 6 on which is mounted a casing orhousing I which is shown on a larger scale in elevation in Figures 5 and12, the point of view being the same as in Figural, and is also shown invertical cross section in Figure 6, and in plan in Figure 9. The housing'1 contains a bearing tube 8 which is elongated in' a direction parallelto the plane of Figure 1, and is horizontally disposed. At its ends itis provided with bearings 8' and 8". The tube 8 encloses the operatingshaft 9 which slides and turns in bearings i3 and 8". The swinging armin on. which the work'presenting mechanism H is mounted is secured tooperating shaft i! as hereinafter describedl' Figure 1 shows blank l2being presented to grinding wheel I 4 by said mechanism 5! which islocated on a moving base l0 integral with arm in.

The grinding wheel is is driven by belt I 5, Figure 1, operated by anelectric motor it. As shown, the grinding wheel, is is carried by arotary head ll which also carries the motor IS, the head comprising abase plate ill and being mounted for adjustment about an axis which ishorizontal and parallel to the plane of Figure l and to the axis ofshaft 9. The plate i8 is marked to cooperate with a .vernier ill, orscale on the bracket .29, and the. bracket 20 is mounted on verticalways 7 2! to move up and down, the bracket being adjusted by means of avertical screw 22 on which a bevel gearM is-mounted in driving relation'1 The vertical ways'2l'and the screw 22 are carried by a stationaryupright 25 mounted on the standard I back of the casing 'l and table 2and this upright carries a hand wheel 26 which operates. a bevel pinion21 by which the gear'24 and hence screw 22 are rotated to move the headI! up and down. The normal adjustment of the grinding wheel surface hasalready been described.

The bracket or carriage 20 is provided with clamping screws 28, forpurposes of fixedly positioning the carriage as to adjusted operatingposition. The hand wheel 26 may be provided with micrometer markings orgraduations as indicated at 29 and a zero marking on the fixed bearingportion of the machine as indicated at 30 for purposes of indicating anddetermining the vertical position of the grinding wheel carriage and/orthe grinding wheel member l4. In the cutting operation in the form ofthe invention herein disclosed, as illustrative, as already pointed out,the cutting or grinding surface of the wheel indicated by referencecharacter 32, and particularly the bottom element or line of the same at32 in Figure 21 where grinding takes place is substantially horizontal,and in the initial position for cutting the radial helically surfacedteeth, the axis of the blank is likewise horizontal and in the sameline, the blank from this position being rocked and moved in grinding asalready suggested. The wheel is offset downwardly as already describedwhen the offset helical surfaces are to be ground or generated tocooperate with the pin in the pin type of clutch. The radial motion ofthe blank, and the rocking of the blank about the transverse axisalready mentioned are accomplished by the swinging arm l0 which iscarried by the operating shaft 9 which rocks and slides to give thedesired motion of the blank from the above stated initial position whichmay be actual or theoretical.

The sliding motion of the shaft is accomplished by means of the swinginglever 33 which is shown in plan in Figure 7. To engage this lever, theoperating shaft 9 is provided with a rotary head 34 which is mounted onthe end of the shaft by means of ball bearing 35 as shown in Figure '7.The lever is fulcrumed on a support 36 which is provided with two ormore fulcrum positions, the fulcrum being indicated reference character31. Another position of the lever 33 to give a different path of motionof the shaft 9 as in grinding the opposite surfaces of the teeth isshown in dotted line in Figure 7. The fulcrum may be shifted from 3! to31' for this purpose changing correspondingly the path of shaft 9. Thelever 33 is pivotally connected at 38 to and with the rotary head 34 ofthe shaft 9 and the lever at its end opposite to the fulcrum 31 has ahandle 40, the extreme motion of which is controlled by stops 4| and 42which are adjustably mounted on a suitable support 43 shown in plan inFigure '7 and in elevation in Figure 1. This operating lever or handlever 33 provides for the radial motion of the blank in grinding, i. e.,in a horizontal line parallel to the plane of Figure 1 which is the lineof the axis of shaft 9, but these details are merely for illustration,it being conceivable that the angle of the machine may be changed,and/or the motions described varied without loss of all utility, andthat the relative motions of the blank and grinding wheel may beotherwise accomplished within the broader scope of the invention.

To rock the shaft 9, and the arm Ill and base It) which carries the workpresenting mechanism H, the shaft 9 is provided a roller arm 45 which isbest shown in Figure 6. This roller arm 45 is engaged with the shaft 9by means of a screw 46 which is threaded in an axial direction into theshaft 9. The arm 45 has the flat shoulder 41 which bears against a flatleft surface 48 on the shaft, this surface is duplicated at 48, 48' atthe two ends of the axial threaded hole 46' so that when the shaftbecomes worn it can be turned over and the arm 45 inserted from theopposite side. This flat portion 48' is shown in plan in Figure 9 wherethe bearing tube 8 is broken away.

The roller arm 45 carries at its outer end remote from the shaft 9, aspherical roller 50 which slides or rolls in a groove or guide slot 5|of a cross section which corresponds to the shape of the sphericalroller 50. This groove is formed in a rotary guide plate 52 which isshown in axial section in Figure 6. The guide plate 52 is mounted torotate about a pin 53 which as shown in concentric with the plate 52.The groove or guide slot 5| which is shown in plan in Figure 8 isstraight and parallel to the diameter of the plate 52. As shown, oneside of the slot 52 is practically diametrical. The rocking of the arml0, and the shaft 9 is controlled by adjustment of the plate 52 aboutthe pin 53 to determine the angle of the guide slot or groove 5|. Thepin 53 is seated in the base I of the casing I which is secured topedestal on table 2.

In the operation of the machine, the angle of the generated or groundsurface of the tooth, and the angle of the helix which in the form oftooth shown and described is 15 to the axis at a point half way betweenthe radial inner and outer edges of the tooth surface is determined bythe position of the plate 52, the angle of the guide slot or groove 5|to give the type of tooth described, and having particular reference tothe surfaces which transmit the power in the right handed rotation ofthe clutch, the guide slot 5| would be at 45 to a north and south lineas seen in the plan, Figure 8, the guide slot 5| extending in anortheasterly and southwesterly direction as seen in said plan, thefront of the machine being at the right in said figure which is thedirection from which Fig. 8 is to be considered in applying thisdescription. The periphery of the plate 52 is provided with index 54 andthe surface 55 on which the disc 52 is supported is provided with asuitable pointer 56 to cooperate with said index or vernier.

It should be noticed that the plate 52 is clamped in its adjustedangular position by means of a screw 68 provided with a hand grip or across pin 69 and bearing against the inclined surface of the plate 52 at10, the screw 68 is threaded into a suitable upright H which forms theend of the frame or casing I.

In the arrangement of the machine and of the disc 52 as illustrated inthese figures, the blank moves and swings from a center position withits axis in the vertical plane of the axis of the grindof the axis ofthe grinding wheel, the blank in ing wheel M, in which position the axisof the blank is horizontal to a position in which the outer end edge ofthe tooth is in the vertical plane this position having rocked throughan angle of 20 as illustrated in Figures 21 to 25. The relative, and notthe actual positions, affect the result.

The swinging or work supporting arm I0 is mounted on the end of theshaft 9 which is at the left in Figures 1 and 5. The end of the shaft 9is flanged at 58 and it has the central axially aligned circular hole59. The arm ill at its right hand end is provided with a stud which isseated in the hole 59 and rotatable therein for purposes of adjustment,the parts being carefully lined by grinding, etc. The arm i9 is furtherprovided with a circular flange 6| having a surface 6| at right anglesto the axis of the stud 60 and of the same diameter as the flange 58,and a cylindrical surface of the flange 6| at52 is provided with anindex 63 or a vernier which cooperates with the suitable point 54 on theedge of the flange 58 to determine the angle of the blank and presentingmechanism in the initial position, and the arm Ill is clamped inadjustedposition by means of a screw 65 which is coaxial with the editstudtfl and the shaft 9 and passes through the stud 69 whichissuitablybored and beyond the stud 69 from the left end of the stud 69to the,

73 which is welded tothe rear edge of the upright end-II of easing .I.:An enlarged collar 8 formed on the end of the bearing .8". of the'shaft9 just outside casing I as shown in cross section in Figure 13 issupported on the block 13 by means of screws 15, and, as shown inFigures 13 and 5, this bearing is split at I4 in the direction of theaxis, and this split is adjustably closed or drawn together by a screwI5. Figure 5' also shows a screw I1 seated in the collar on onetside ofthe split, and bearing on the other si'de'of the same,

by which the slit "I4 may be opened to free the 1 bearing, and'Figure 5,and also Figure 13 further show a screw '18 supported in a suitableear'19 on .y the frame by which the bearing maybe raised as desired togive the desired adjustment and alignment ofthe bearing and of shaft 9,and to give just the right degree of freedom for turning with out play.The portion of the shaft which is ex posed outside the hearing at theleft in Figure5 is covered by a chamois bag .or other suitableprotection '80, and other bearings are similarly protected. It willbeunderstood that when'the arm I9, andbase I9 are properly adjustedabout the shaft 9, the arm I9 is clamped by means of the screwtightenedby means of the handle or arm 6?. Every precaution is taken togive the machine the desired accuracy. The right hand end of the shaftB'adjacent bearing 8' as shown in Figure 12 is protected by a similarcham'ois bag to that shown at 89 and the bearing 8' has a clamping screwBI to hold the shaft 9 stationary for purposes of adjustment of shaft[9. v

vThe work presenting mechanism I I shown and briefly discussed inconnection with Figure 1 is illustrated in plan in Figure 4, in frontelevation in Figure 10, and Figure 2 which is a view look-f Havingparticular ingfrom the left in Figure 1. reference'to Figure 2, theblank I2 is mounted on the splitexpanding end 86 of an "arbor The split.tapered end 86 of said arbor is expanded within the central opening I2of the blank. I2 by means of a screw 8'! having a tapered flaring head.The screw 8'! is threaded into an opening which is axially located inthe arbor. I This hole is tapered at its outer end in correspondencewith said screw 87. The arbor 85 is shouldered at 85' to position andsupport the blank I2, and is in turn externally tapered at 88 to fit ina correspondingly tapered hole 89' in a plug-carrier 89 which fits in atapered hole 99 in a tapered presenting member 9| which is mounted intapered bearing 9I' in the housing 95. .Member 9I,

turns about the arbor axis for purposes of adjustment of the blank inmoving it to expose first one tooth surface and thenanother to thegrinding wheel, and also in grinding; The'presenting member 9| is turnedby means of knurled head 92 at the left in Figure 2. This knurled head92 has seated therein concentrically therewith a boss 93' formed on-thehead 93'of a clamping screw-9l which is threaded into the rearf-end ofarbor 85 :in an axial direction and serves to clamp the arbor -85 in andto'the presenting member 9-I and also to clamp the blank which iscarried :by the arbor to" the presenting member 9|. For the purpose ofclamping the screw mem- I ber. 94 in fixed relation 110111118 arbor 85the head 92 is providedvwith a split portion 92"? ,and atake up orclamping screw 92', as shown particularly in Fig. 4 ofthe drawings.

- 'I'hevwork presenting member 9i also includes an index plate H4 whichis integral with mem berti and has notches or engaging-points-arcuatelyspaced about the arbor axis. Theseare selectively engaged by a springcontrolled looking tooth or other engaging member I I? shown as carriedby sliding bolt H8 which slides in the arm 99 and locks the arm 98 andits roller'shaped end 99 to the index plate H9; and hence topresentingmember 9i. The bolt H8, and particue larly the tooth Hi, are normallyadvanced by a spring I I 9 which, as shown, is inside the bolt and abutsagainst 'a-stationary cross pin 5 I9, theqbolt H9 being suitably slottedto provide for sliding relatively to pin H9. The spring holds tooth II-Inormally in engagement with one of the notches M5. by withdrawing thepin I Is by means ,of knob H8 is rotated with the. presenting member 9:by'means of the knurled head 92 to give the desired angular position ofthe blank I2 about its axis.

The work presentingv mechanism is mountedongway I29 integral with aplate I9" mountedon the base I9 at the end of arm It, being adjustablysecured by screws I69 and it! to correct forangularity as in Figures 23and 30. The way engages a groove-I23 in the base IZI of casing 95, andthe alignment of the head.- or work supporting mechanism II is correctedand adjusted by means of screws I2I which bear against gib I.22,ingroove I23 which in turn bearv against. the side of way I29. Thework-presenting assembly II- is adjusted toward and from the: operatoralong waysIZU by-screw. 96. I

The .housing'95for the presenting mechanism with the presenting member9I therein which member 9I'in turn carries arbor 85 and the blank I2 ismounted for adjustment along ways heren;-

llO

The index plate H4 when'released about the axis of the member 9i and hasa roller shaped outer end 99,said roller shaped end being enclosedwithin a carrier I99 mounted :on

a sliding carriage IIiI which slides transversely to the arbor axis inways I92 inthe casing head I93 which is attached to housing of. the workpresenting mechanism II. This carrier I ill is provided with a rack I04,Figure 1-0, which'is engaged by a pinion I95 which pinion is carried onand operated by a shaft I96, Figure 2, which is parallel to the axis ofthe blankcarrying, arbor 85,-and extends at right angles to the plane-ofFigure 1. This shaft I96 has a knurled head i9? which isclearly seen inelevation in Figures-1, 2, land 10. The carrier I09 isalso engaged byop:

positestopfiscrews 19B and. I99, see particularly Figures 2 and 10.These screws as aforesaid are,

on opposite'sides of the carrier I99 in the direction of the rack lul/and theyare adjusted-back V and forth as desired to give the desireddepthof grinding. -Each screw I98, E99 is provided with aspring controlto prevent undesired; rotation. This consists of. a hollow nut I I9for'each screw, eachnut: being provided with anj arm I I Iv which restsin a socket 2 in the casing I03; The screws I08 and I09 as hereinafterdescribed, are adjusted to determine the depth of cut at each grindingstroke, and are held in adjusted position by the pressure of springs I II within the hollownuts II 0.

Figure 14 illustrates a gauge I24. This View may be called a frontelevation as it is taken from the same direction as is Figure 1; Figure15 being a view looking from the right in Figure 14. Cooperatingportions of the machine in Figures 14 and 15 are shown in broken lines.The gauge comprises a bar I25 which, in the use of the gauge, is in aplane parallel to the plane of Figure 1. This bar I25 has at one end acircular depending disc I26, which is circular ina plane transverse tothe length of bar I25. This disc is adapted tobe seated in and to fitthe support I27 as turned and adjusted as hereinafter described, thesupport being shown in Figures 1, 2, 14, and 15. The gauge I24 has atits opposite end a foot I28 which, as shown, has a circular concavesurface I29 adapted to engage the head 65' of the clamping screw 65 inFigures 5, 14 and 15, the handle 61 being removable. The bar I25 isprovided intermediately with a straight edge I28, shown in side view inFigure 14, and in end elevation in Figure 15, both being the operativeposition of the gauge in which the centers of the surfaces, I26 of discI26 and I29 are in alignment, the surfaces being concentric and thestraight edge I28 is aligned by means of dowel pin I30 with the axes ofthese two surfaces. In setting the machine, the straight edge I28engages the radial line at the center of the tooth surface of the blankI2 which is to be first ground as indicated in Figures 14 and 15, thecenter being half way between the peak and the base of the tooth at I3,Figure 15, and it may be otherwise located.

The cutting or grinding surface 32 of the wheel I4 is trued by means ofa diamond or a suitable cutter I3I shown in Figures 16 and 1'7, and alsoin the general view, Figure 1. In the construction shown, the diamond orcutter I3I is secured to a shank I32 which is in turn mounted in acarrier shaft I33 which is adjustably mounted in a clamping guide I34which is slit at I35 in the direction of the shank I32, and the slit isclosed by a screw I36 which is operated by an arm I31. The carrier shankI33 is shown as provided with a pin I38 which slides in the slit I35 asa way, and prevents the member I33 from rotating. The carrier I33, andthe diamond cutter carried thereby are adjusted in the direction of theguide by means of a screw I39 operated by a thumb nut or other nut, I40carried in a suitable slot in the guide I34. The diamond cutter ismounted on a base I4I which is secured to the table, i. e. the top ofpedestal I43 by means of a screw bolt I42. The guide I34 is inclined asshown in Figures 16 and 1'7, to provide a suitable cutting angle in itsengagement with the wheel I4 and particularly the grinding surface 32thereof. The upper surface of pedestal I43 at I44 is finished in theplane of the top surface I44 of the pedestal 6, both planes beinghorizontal.

Cooperating with the diamond I3I, I have shown a gauge indicated in ageneral way by reference character I45. The important feature of thisgauge is that it has a downwardly disposed horizontal gauge surface I46which, in the operative relation of the parts as shown, is in the samehorizontal plane as the axis of the shaft 9. The gauge I45 as shown hasa base I41 adapted to rest on the top surface I44" of the pedestal I43,and in this position, the"preferrfed form of gauge shown, supports thegauge surface I46 in the plane above described, i. e. the horizontalplane of the axis of the shaft 9. This gauge surface I46 serves asillustrated in Figure 16, as a means for setting the diamond or cutterI3I, so that it is adapted'to finish the grinding surface 32 of thecutting or grinding wheel I4 so that its bottom or grinding element 32as indicated in Figure 16 is in the horizontal plane of the axis of theshaftv 9. As it rotates, the position of the bottom element or grindingplane of wheel I4 is of course maintained at all points, the wheel beingcircular about the axis of its shaft.

The construction already described provides for the adjustment of thediamond I3I into this gauge plane or cutting plane I46 and for clampingit in this position for operation as described.

The upright 25 which supports wheel or stone I4 being stationary, andthe diamond point I3I being mounted on the table 2, to surface the wheelI4, the table is released by releasing the clamp 3, and is moved byrotating the hand wheels 4 and 5 to bring the diamond point in contactwith the cutting surface 32 of the wheel I4 whereby this surface is cutso that its bottom element is in the horizontal plane of the axis ofshaft 9 as already described. This is the grinding line hereinafterreferred to. In this respect the dressing diamond I3I may be readilyplaced in fixed aligned position with the longitudinal axis of thegrinding wheel I4 upon the table 2 being moved suificiently to the rightin Figure 1 of the drawings, whereby, the male portion 3 of the socketclamp member 3 may be placed in registered engagement with the femaleportion of the socket clamp member 3".

Figure 17 shows the spacing plate I48 placed against the gauge surfaceI46 whereby the plane to which the diamond point I3I is adjusted islowered below the plane of the axis of the shaft 9 by a predetermineddistance. This provides for grinding the clutch blank with the toothsurfaces in a helix, the axis of which is spaced from the axis of theclutch member by a distance which may be half the width of the pin inthe pin type of clutch illustrated in Figures 19 and 20. This operationwill be more fully described.

Figure 11 shows the diamond point and its support with a mantel I49 toprevent the grit from coming in contact with the delicate bearings andother parts by which the diamond point is adjusted, and maintained inthe desired position.

In the operation of the machine, the first step is to set the machine.Initially the table 2 is clamped by closing the clamp 3. In Figure 1there is a gauge mark I50 on the casing I. This gauge mark is also shownin Figure 5. In order to bring-the center of the arbor 85 into thevertical plane of the axis of the wheel I4, an arbitrary method has beenadopted. This consists in moving the "shaft 9 by means of the lever 33to a positionin which the left hand edge I5I of the bange 58 is '5inches from the gauge mark I50. This brings the axis of the blank andthe arbor above mentioned which are identical into the vertical plane ofthe axis of wheel I4. The wheel I4 has already been set and trued bymeans of diamond point I3I so that the bottom cutting element 32 of thegrinding surface 32 is horizon tal andin the horizontal plane of theaxis'of shaft'9. In cutting a right hand helix, it is understood thatthe blank being cut atpresent is of the type in which the helicalsurfaces already describedare radial, i. e. the axis of the helix isidentical with the axis of the clutch and the surface ground is thepower transmitting surface in right handed rotation of the clutch, andit is further understood that the clutch member or blank chosen forillustration is two inches in diameter having a one inch counter-bore inthe center so that the radial length of each tooth is one-half of oneinch. The presenting assembly II which is secured to the shaft 9 beingon the arm I0, is now advanced one inch to the left as seen in Figure 1which brings the outer radial end of the tooth to be ground into theVertical plane of the axis of the grinding wheel.

It should also be understood that part of they of Fig. 8 is to betreatedas the bottom or south side of the map.

It is also understood that the blank I2 would be clamped to the mandrelor arbor 85 and the tooth surface I2 to be ground would be set by meansof gauge I24, Figures 14 and 15 with the central line of the toothsurface at E3, in Figure 15 in a horizontal plane, the center of thetooth surface which has first been roughed out to substantially theproper form being in contact with the knife edge 128 of the gauge whichbrings its center line I3 into. line with the axis of the shaft 9, whichin this machine is horizontal and sometimes referred to as the line ofgeneration.

When the work support has been brought to the position above indicatedwith the radial outer end of the tooth I2 in the vertical plane of theaxis of grinding wheel I4, the arm I0 is released by backing screw 65 byhandle 61 and turned in left handed rotation as seen from the left inFigure 1 till the blank axis and the axis of arbor 85 are inclined at 20to the axis of the arbor 85 in intial position in the vertical plane ofwheel I4 which position of the arbor axis in the machine shown ishorizontal. It is likewise true that in this position of the machineshown the grinding line 32 coincides with the arbor axis extended.

By turning the blank and arbor 20 as described, the blank I2 is rockedbackwardly to the position shown in dotted lines in Figure 22 from theposition shown in full lines in said figure. While this figureillustrates the grinding of the opposite surface of the tooth, theinclination is the same. This places the blank in the relation to thegrinding wheel which it should occupy in the position of grinding orcutting the surface of the tooth at the outer radial end. The angle maybe measured by Vernier 63, 64. Next the arm ii) is clamped to shaft 9.The angle of the tooth at its outer end, as already explained, is 20 tothe-axis of the clutch member, the tooth being identified as 15 tooth,i. e. one having a 15 incline at a point half way between the radialends of the tooth and 10 at its inner end. At this period of theoperation, the index plate H4 is locked in the position shown in Figure10. It may be considered that the stop screws I08 and I09 are as thereinillustrated, and the blank and arbor are held in corresponding position.

. In order to provide for the depth of the cut,

the stop screw I09 is backed off by a distance which can be determinedby the operator having a slight degree of familiarity with the machine.The lever 33 is then moved to the right'in Figure 1 whereby the surfaceof the tooth is passed over the grinding wheel and it will be noted asthe surface of the tooth passes over the grinding wheel the blank isrocked as illustrated in Figure 22, and in other figures, by means ofthe follower Eli operating in the slot or guide 5i as illustrated inFigures 6 and 8. After each passage of the blank over the grinding wheelthe head I07 is rotated by the operator, rotating the shaft I06 and thepinion I05 moving the rack I0 whereby the blank is slightly rotated. andfed to the cutter determining the thickness of each cut.

A refinement which is of importance has already been suggested inconnection with Figure 25. As the blank is rocked through the positions7 Figures 23, 24, and 25, the base of the tooth at I56 moves away fromthe edge of the grinding wheel at I51, leaving a spaceindicated byreference character I58 between the stone and the base of the blank. Tocompensate for this motion the work support is slightly rotated in ahorizontal plane as hereinafter described.

' This is best illustrated in Figure 4. For this purpose, the bolts Iand NH are loosened, the work support indicated by reference character II in Figure 1, i. e., the work presenting assembly on the arm I0 ismoved relatively to said arm by swinging it slightly about the bolt I60,this motion being provided for by the slot I 62 in the base I0 in whichthe bolt IGI is located. This swings arbor 85 in the plane of its axisand the axis of shaft 9, the corrections being different for differentcuts. The bolts I56 and I6! are then tightened and the grindingoperation already described is carried on until metal to the desireddepth of cut as determined by the stop I08 has been removed. The effectof swinging the work support I I is illustrated in Figure 26.

When the depth of the out has been determined to the satisfaction of theoperator, and one surface it has been generated by continuing thecutting until the radial arm roller carrier I651,

contacts the adjusted stop I08, the initial surface being thuscompleted; each successive surface to be thereafter generated is broughtto the grinding plane by releasing the index plate II I by withdrawingthe pin H8 and tooth III, and turning the plate IM and presenting member9! by grasping the knurled head 92, see Figure 2, to a predeterminedposition in which the pin H8 being released by the operator the toothIIl engages a predetermined notch II5. When this setting has beenaccomplished, the out is completed by a series of strokes of the lever33, the blank being advanced after each stroke by rotating the knurledhead I @I in Figure 2 and hence the shaft Hi6, and thus moving the blankby way of the carrier IEIB and radial arm roller portion 99 as alreadypointed out, it being understood that the blank is thus moved throughand by way of the lever 88 and index head H4 which is attached to therotary presenting member ill.

The faces, the grinding of which has been described, are the powertransmitting surfaces in the-right handed rotation of the clutch. Whenand if it is desired to grind the opposite faces of the teeth which isless essential unless the tools are to be frequently reversed, the disc52 is unclarnped and rotated to a position in which the guide'slot 5| isinclined in a northwesterly and southeasterly direction as seen from theright in Figure 8 which corresponds to the front of the machine as seenin Figure 1, the previous out having been made with the guide slot in anortheasterly and southwesterly direction as seen from the right inFigure 8 it being understood that Fig. 8 is to be treated as a maphaving its south or bottom end at the right in Fig. 8 as seen from thebottom of the sheet. The setting operation already described is reversedand the teeth are ground by the same operation already described whichis believed to be easily understood in View of the previous description.The cutting of clutch members of the toothed variety for the type ofclutch shown at I65 in Figure 19 has already been suggested. In thistype of clutch, the operative surfaces of the teeth of helicalarrangement are formed on an axis which is offset from the true axis ofthe clutch by a distance which corresponds to half the thickness of thepin I66. To effect this operation, the grinding wheel I4 is lowered, butit still keeps its grinding line 32', i. e., the lower portion of itsgrinding surface 32 in the vertical plane of the axis in a horizontalposition. Figure 1'7 illustrates the gauge plate I48 which is of theproper thickness and is placed beneath and in contact with thehorizontal gauge surface I46, the diamond point I6I is then adjustedinto contact with the lower gauge surface I46 of the plate I48.

The carriage 2 is unclamped, and the diamond point I35 is by means ofthe operation of hand wheels 4 and 6 moving the table 2 suitably in alongitudinal direction, as hereinbefore described for purposes of fixingthe diamond point I3I in aligned position with the longitudinal axis ofthe grinding wheel It by means of the clamping elements 3 and 3", andthence in transverse directions passed over the cutting surface 32 ofthe Wheel It to true the same in the desired plane.

The initial setting of the machine is the same as previously described,the table first being returned to cutting position and positioned andclamped by means of the clamp 3 which is adapted to both positioning andclamping of the table in the cutting or grinding operation. The maindifference between this grinding operation and the one for the radialteeth aside from the setting of the wheel, is brought out in Figures 27and 28 and 29. It may be assumed that with the cutting or grinding wheelI l lowered with its cutting element below the center of the blank aswould be essential to the adjustment already described, the blank inswinging from the initial to the 20 position as it is passed over thewheel, tends to bring the cutter into such relation with the blank thatit would tend to out below the base of the clutch member. Figure 2'?shows a blank I65 in the initial upright position in which its axis isin the vertical plane of the axis of the wheel. Figure 28 shows theblank moved away from the wheel by turning the housing 95 and the entirepresenting mechanism. This displacement avoids cutting into the base I61of the blank between the teeth as already suggested. Figure 29 shows therelation of the cutting wheel to the blank in the 20 position when theouter radial end of the tooth is being ground and shows that the edge I!of the wheel comes only to the base I61 at this time and does not cutinto it. This adjustment is accomplished by loosening the nuts I60 andNH, Figures2 and 4, and swinging the carriage or assembly I I in Figure1 to the left in Figure 4 instead of to the right to a degree sufficientto provide for the proper relation of the wheel to the blank as alreadyexplained. The

nuts I60 and NH are then tightened. The grinding of the tooth surfacesis then carried forward as already described in connection with theradial type of clutch member, i. e., the member having the toothsurfaces helically arranged on the axis of the clutch.

Figure 18 shows two clutch members having their tooth surfaces inhelical form, the helix being formed about the axis of the clutch, theclutch members being I2 and I2", and substantially identical,

Figures 21 and 22 show the helical type of clutch member, the full linesshowing the clutch member in the position in which its axis ishorizontal and in the vertical plane of the grinding wheel. This is nota cutting position for the blank, it being essential that the blankillustrated be moved one-half inch off center in the direction of arrowshown in Figure 21, before cutting takes place as to the left clutchtooth surface indicated at I2' or in the opposite direction for cuttingthe tooth surface on the right of said clutch, thus it is necessary tomove the blank as shown one-half inch off center before cutting takesplace in either direction. The arrangement shown is for grinding thesurfaces which engage in the left handed driving relation, 1. e., thesurfaces I2'. In the operation, the blank is moved to the right from thecenter position; The dotted line position in Figure 22 shows the blankrocked through a arc which corresponds to the end of the out, thegrinding wheel I4 engaging the outer radial end edge of the toothsurface at the one inch radius. Other sizes of teeth and other angles ofhelix may be cut. This operation is opposite to that first described,the angle of the blank at the time of cutting the outer radial end ofthe tooth is the same, but the surface being ground is at the left ofthe center of the arbor 85 in- Figure 1, and the path of the blank iscorrespondingly different.

Figure 23 illustrates the cutting position in which blank has beenturned through a 10 are from the horizontal or from the 20 position andthe cutter or grinding wheel is engaging the corner point or edge I10 ofthe tooth nearest the center as shown in Figure 21. Figure 24 shows theintermediate cutting position when blank has been rocked through a 15arc, it being understood that the center of the tooth is inclined at a15 angle to the axis. Figure 25 shows the position of the grinding wheelI4 when the blankhas been rocked through a 20 are without the finalcorrective adjustment about the bolt I60 as shown in Figure 4. Figure 26shows the final cutting position for the outer edge of the tooth afterthis correction, the edge I52 of the wheel being in contact with thebase of the tooth at I56. Figures 2'7, 28, and 29 already described,have relation to the olfset tooth i. e. the type which cooperates withthe pin I66, as illustrated in Figure 19. Figure 30 is a horizontalsection on the axis of the clutch member, the angle I73 being the anglethrough which the blank is rocked by the adjustment at the bolts I60 andI6I to give the correct relation of the Wheel I4 to the blank I2 asillustrated in Figure 26. The dotted line I'M shows what would be thepath of the out if the blank were not turned in this way. Figure 31 is aplan view of a two inch blank of the radial helical tooth surface typeshowing the dimensions of the blank, i. e. the figure being drawn twiceactual size. The counterbore I15 is one inch in diameter, and the teethI16 are one half an inch in radial length. The incline of the toothsurface

